查看更多>>摘要：Selective detection of nitroaromatics is still a major security concern in national security and environmental protection. In this endeavor, a new low molecular weight gelator based on the diphenyl imidazole group had been designed and characterized. This gelator could form stable organogels in DMSO and n-butanol solvents. Both pi-pi * absorption and fluorescence emission peaks of the gelator in DMSO showed different shifts compared with it in n-butanol during gelation, indicating different self-assembly modes in the two solvents. In addition, the gelation behavior of the gelator were investigated thoroughly by H-1 NMR spectroscopy, SEM and XRD techniques. Further, this gelator worked as a selective chemosensor for picric acid in solution and gel states with a fluorescence quenching mechanism, and the limit of detection was 1.75 x 10(-7) M and 3.76 x 10(-7) M, respectively. The details of the sensing mechanism were elucidated using H-1 NMR, Job's and Bensi-Hildebrand methods, which revealed a 1:1 binding ratio via the H-bond interactions between picric acid and gelator. Furthermore, the gelator was successfully practiced for the picric acid quantitative analysis in real water samples. The on-site detection technique using paper strips of the gelator could detect PA with the naked eye up to 10(-7) M under UV 365 nm light. This work demonstrated that diphenyl imidazole-based gelator could be a potential soft material for explosive detection.
查看更多>>摘要：Three compounds based on aniline, thiophene and vinylpyrimidine as anchoring group have been prepared and studied as light harvesting units for dye-sensitized solar cells (DSSCs). They comprise thiophenyl pi-spacer systems with one or two thiophenes (AT-Pyri, ATT-Pyri) and aniline as donor which is functionalized, in one case, with an hydroxyl group (HO-AT-Pyri). The bithiophene based dye (ATT-Pyri) shows higher extinction coefficients and smaller transition energy, as well as broader absorption spectrum. Thus, despite lower dye uptake, devices based on one thiophene and with the hydroxyl group (HO-AT-Pyri) have slightly higher power conversion efficiencies (eta) as compared with the analogous dye without this group (AT-Pyri). However, the best performing device is based on the dye with bithiophene bridge (ATT-Pyri) when a co-adsorbent is added to avoid the aggregation of the dye. The photovoltaic parameters of cells based on these vinylpyrimidine dyes are enhanced over 1000 h, especially for ATT-Pyri devices, which reach a eta = 6,4%.
查看更多>>摘要：A facile synthetic approach afforded a new family of AIE active and ESIPT featured A-D-A (Acceptor-DonorAcceptor) type symmetrical triphenylamine centered bis unsymmetrical azine derivatives TPSA, TPHY, TPDS and TPOV. Depending upon the substituent in the periphery, all compounds displayed frail fluorescence in the solution state and exhibited strong multi-color luminescence character in aggregated/solid state. The results achieved from UV-visible absorption, emission and theoretical studies confirmed the existence of the intramolecular proton transfer phenomenon in the excited state (ESIPT). The experimental results affirmed AIE behavior present in the compounds and it might be due to the restriction of the intramolecular rotation (RIR) mechanism. The in vitro antibacterial activity of the compounds was also scrutinized against elected bacterial strains (B. subtilis, S. aureus, E. coli, and P. aeruginosa) in different concentrations (0.5 mM, 1 mM, 1.5 mM). The results revealed that all four compounds have excellent antibacterial activity at 1.5 mM than other concentrations tested in the present study. Further, the fluorescence feature of the compounds was explored via fluorescence microscopy to probe the microbes (Pseudomonas aeruginosa).
查看更多>>摘要：Light-emitting electrochemical cells (LECs) based on ionic transition metal complexes (iTMCs) have become a trend in the field of electroluminescence research due to their simple device structure. However, high cost has become a major obstacle to the development of these precious metal-containing materials. Addressing this challenge, two pyridium-based thermally activated delayed fluorescence (TADF) emitters were designed and synthesized to obtain high-efficiency orange-red-emitting light-emitting electrochemical cells (LECs). Pyridine moiety is used as the precursor of electron acceptor, as well as the embedded ionic part, connecting with different donors, carbazole (CZ) and tert-butyl carbazole (tBuCZ), named Pym-CZ and Pym-tBuCZ. The lifetime measurements showed delayed fluorescence at 2887 and 1746 ns for Pym-CZ and Pym-tBuCZ, respectively, confirming their TADF characteristics. The orange-red emission of Pym-CZ is considered to be due to the strong intermolecular interaction in high concentration, while green emission occurs when the molecules are in monomer form. Notably, compounds Pym-CZ and Pym-tBuCZ are the first pure ionic organic TADF materials for orange-red LECs, and the maximal EQE of LEC based on Pym-CZ reaches approximately 1.2%, demonstrating the potential of a new method for manufacturing low-cost orange-red LECs.
查看更多>>摘要：Inverted singlet-triplet molecules possessing a down-conversion process from the lowest excited triplet state (T1) to the lowest excited singlet state (S1) have recently roused much attention on account of potential merits in organic optoelectronics and photocatalysis. Nevertheless, investigations on inverted singlet-triplet molecules predominantly depend on the sophisticated ab initio calculations, while experimental attempts are extremely rare. In this work, we experimentally demonstrate the inverted singlet-triplet character of a heptazine derivative (HAP-3MF) which exhibits negative S1-T1 energy gaps (Delta EST) of -0.22 eV in toluene and -0.19 eV in acetonitrile based on meticulous photophysical investigations. To the best of our knowledge, this is the first time to directly obtain negative Delta EST based on fluorescence and phosphorescence spectra. Moreover, to better evaluate and reveal the photophysical features of extremely weak delayed emission in HAP-3MF, a mixed solution system of HAP-3MF:1,3-di(9H-carbazol-9-yl)benzene (mCP) in toluene at various molar ratios was subtly designed, and the energy transition mechanism involving a down-converted triplet-to-singlet channel was carefully elucidated.
查看更多>>摘要：Biothiols such as cysteine (Cys), homocysteine (Hcy) and glutathione (GSH) play important roles in regulating the redox balance of life process and are closely associated with human health and diseases. In order to better understand their roles in physiological process and the early diagnosis of related diseases, it is crucial for the selective detection of biothiols in biological systems. In this paper, we developed a 4-phenylselenium coumarin-nitroolefin conjugate as the fluorescent probe for the detection of biothiols. By introducing the 4-phenyselenium as the active site, probe CouSeNO(2) is capable of detecting Cys/Hcy and GSH in dual fluorescence channels. For the biothiols, the first-step sensing reaction is proved to be nucleophilic substitution of 4-phenylselenium by the thiol group. Furthermore, through two-channel fluorescence imaging, probe CouSeNO(2) has been successfully applied to sense the exogenous and endogenous biothiols in living cells.
查看更多>>摘要：Compared with the recently reported large number of fluorescent lipid droplet (LD) probes based on organic fluorophores, phosphorescent LD probes based on transition metal complexes are much less reported. In addition, LDs are rarely studied as targets for photodynamic therapy (PDT). In this work, two lipophilic neutral iridium(III) complexes, namely [Ir(bt)2(hpd)] (denoted as LDIr1) and [Ir(piq)2(hpd)] (denoted as LDIr2) (where Hbt = 2phenylbenzothiazole, Hpiq = 1-penylisoquinoline, Hhpd = 3,5-heptanedione), have been synthesized and characterized. These complexes exhibit long-lived orange to red phosphorescence emission and large Stokes shifts (ca. 160 nm). They can specifically stain LDs in living A549 and HepG2 cells, showing excellent biocompatibility and favourable photostability. Complex LDIr1 has been successfully applied for monitoring of oleic acid-induced LDs accumulation in living A549 cells and in vivo imaging of larval zebrafish. Moreover, these two iridium(III) complexes can efficiently generate singlet oxygen upon visible light (425 nm) irradiation to kill cancer cells effectively by means of PDT. They display impressive high phototoxicity index (PI) values of 1087 and 263 for complexes LDIr1 and LDIr2, respectively. This study provides useful insights into rational design of new metal complex-based LD-targeted phosphorescent probes and PDT agents.
查看更多>>摘要：Peroxynitrite (ONOO-) is considered to be an important indicator of the early stage of drug-induced liver injury (DILI). Therefore, the establishment of a reliable ONOO- detection method is of great significance for the early prediction and diagnosis of DILI. In this paper, a red fluorescence probe BDP-PN based on BODIPY dye was constructed studiously for large signal-to-noise ratio, highly selective and sensitive recognition of ONOO- in vitro. Furthermore, the probe has been successfully used to image exogenous and endogenous ONOO(- )in different cell lines. More importantly, in the APAP-induced liver injury model of diverse cell lines and mice, BDP-PN not only could monitor the up-regulated expression of ONOO-, but also could evaluate the remediation of NAC. In addition, BDP-PN could distinguish cancer cells from normal cells by the different levels of ONOO- expression. All the results demonstrated the wider universality of probe, which may as a promising tool to diagnose drug induced liver injury by means of monitoring fluctuation of ONOO-.
查看更多>>摘要：Our work was related to the systhesis of several nonlinear optical dendrimers L1-L3 with identical Bis(N,Ndiethyl)aniline-derived donor bridge and phenyl-trifluoromethyl-tricyanofuran acceptor. The dendritic structure of multichromophores can effectively reduce the electrostatic interaction between chromophores. And the strong acceptor result in large first-order hyperpolarizability of the chromophores. Multichromophores L2-L3 showed very high poling efficiencies due to large steric hindrance and first-order hyperpolarizability value of chromophores. A large poling efficiency (2.10 +/- 0.08 nm2/V2) and r33 (205 p.m./V) have been achieved for neat chromophore L3 thin films at 1310 nm. Besides, the glass transition temperature (Tg) of L2 and L3 has greatly improved to 125 degrees C and 133 degrees C, respectively. All of these provided an new insights into molecular design of chromophore with enchanced poling efficiency and high thermal stability.
查看更多>>摘要：Here we present highly ordered nitrogen doped fluorescent carbon nanoparticles (N-CNPs) as fluorescent probe prepared by controlled heating of ethylene glycol and alanine anhydride at 170 degrees C for 120 min. The probe exhibits bluish fluorescence at lambda(emission) = 452 nm when excited at lambda(excitation) = 380 nm, with fluorescence quantum yield of 7.6% and average lifetime of 5.8 ns The structural and compositional studies of N-CNPs by Raman Spectroscopy, Fourier transformed infrared spectroscopy, X-ray photoelectron spectroscopy, H-1 and C-13 NMR and higher resolution transmission electron microscopy indicated formation of highly ordered N-CNPs via oligomerization of ethylene glycol with alanine anhydride. The probe has been optimized for detecting trace level of important biomarkers as analytes, e.g., norepinephrine epinephrine and dopamine via fluorescence recovery mechanism. Here, MnO4 were instrumental in recovering the fluorescence. The fluorescence recovery index is linear with the concentration of the analytes of interest and satisfied the Stern-Volmer equation. The Limit of detection (LoD) of epinephrine (88 nM) and norepinephrine (91 nM) are better than the LoD of dopamine (140 nM). The selectivity towards detection of epinephrine, norepinephrine and dopamine has been established with respect to several biologically relevant molecules as interfering agents. The feasibility of this analytical methodology in detection of epinephrine, nor-epinephrine and dopamine in real sample has been demonstrated by spike analysis in human urine samples. over line is used for quenching the fluorescence intensity of the probe while the analytes
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